Final answer:
After 100 years, approximately 218.75 grams of lead-210 will remain out of the initial 7000 grams.
Step-by-step explanation:
To determine how much of the initial amount of lead-210 will remain after 100 years, we need to consider the half-life of lead-210. The half-life of lead-210 is the time it takes for half of the sample to decay. According to the information provided, we know that after one half-life, the amount remaining will be half of the initial amount.
Let's calculate the number of half-lives in 100 years. Since the half-life of lead-210 is not given, we'll assume it to be 20 years for this example. Therefore, there would be 5 half-lives in 100 years (100/20 = 5).
Starting with an initial amount of 7000 g, after each half-life, the amount remaining will be half. So after the first half-life, the amount remaining will be 3500 g. After the second half-life, the amount remaining will be 1750 g. After the third half-life, the amount remaining will be 875 g. After the fourth half-life, the amount remaining will be 437.5 g. And finally, after the fifth half-life, the amount remaining will be 218.75 g.